title: Sonographic 'molar tooth' sign in the diagnosis of Joubert syndrome.
abstract: The characteristic imaging finding common to Joubert syndrome and related disorders is the 'molar tooth' sign. The prenatal diagnosis of Joubert syndrome using both ultrasound and fetal magnetic resonance imaging (MRI) in families with an affected child has been reported previously. We report two cases in which the molar tooth sign was identified by sonography at 26 + 4 weeks and at 20 + 6 weeks, respectively, prior to fetal MRI or genetic testing. In both cases the finding was subsequently confirmed on fetal MRI. As definitive prenatal genetic testing may not be conclusive in Joubert syndrome, the ability to identify the molar tooth sign sonographically before 24 weeks provides a valuable adjunct to prenatal diagnosis.
authors.affiliation: Department of Radiology, Division of Maternal-Fetal Medicine, British Columbia Women's Hospital and University of British Columbia, Vancouver, BC, Canada. dpugash@cw.bc.ca
authors.forename: D
authors.initials: D
authors.lastname: Pugash
authors.forename: T
authors.initials: T
authors.lastname: Oh
authors.forename: K
authors.initials: K
authors.lastname: Godwin
authors.forename: A J
authors.initials: AJ
authors.lastname: Robinson
authors.forename: A
authors.initials: A
authors.lastname: Byrne
authors.forename: M I
authors.initials: MI
authors.lastname: Van Allen
authors.forename: H
authors.initials: H
authors.lastname: Osiovich
mesh_terms: D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D001921:Brain / Q000002:abnormalities / Q000196:embryology / Q000473:pathology*; D002526:Cerebellar Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D002531:Cerebellum / Q000002:abnormalities; D004453:Echoencephalography; D005124:Eye Abnormalities / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D011247:Pregnancy; D011256:Pregnancy Outcome; D011296:Prenatal Diagnosis; D012160:Retina / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000473:pathology; D016216:Ultrasonography, Prenatal